Starting system for thermal prime movers



y 13, 1954 T. J. WARRICK STARTING SYSTEM FOR THERMAL PRIME MOVERS Filed Ma? 15, 1952 Inventor: Thurlow J. Warrick by WW His Attorney.

Patented May 18, 1954 UNITED STAT OFFICE STARTING SYSTEM FOR, THERMAL PRIME NIOVERS Thurlow J. Warrick, Erie, Pa., assignor to General Electric Company, a corporation of New York 9 Claims.

This invention relates to starting systems for thermal prime movers, such as diesel engines, and more specifically to a system for automatically starting such a prime mover.

Thermal prime movers, such as diesel engines, are commonly started by one of two methods; either by injecting compressed air into the cylinders or by cranking the engine with an electric cranking motor. Where the engine is used as a prime mover for an electrically driven vehicle, it is ordinarily mechanically connected to drive a traction generator and it is therefore feasible to utilize this generator as a motor energized from the vehicle batteries to crank the engine. In

such a system, it is desirable that the starting of the engine be automatic, i. e. initiated by the closing of a single switch and the various steps of the starting sequence thereafter accomplished automatically. Further, it is desirable that the starting system include certain additional features, for example, automatic breaking of the cranking connection in the event that the engine fails to fire in a predetermined time, and automatic connection of the generator to the battery for charging in the event that the engine did fire and is operating satisfactorily.

It is, therefore, an object of this invention to provide a system for automatically starting a thermal prime mover incorporating the features enumerated above.

Further objects and advantages of this invention will become apparent and the invention will be better understood by reference to the following description and the accompanying drawing, and features of novelty which characterize this invention will be pointed out with particularity in the claims annexed to and forming a part of this specification.

In accordance with this invention, a thermal prime mover, such as a diesel engine, is mechanically connected to drive a generator, the generator in turn being provided with series and shunt field exciting windings. A battery is included in the system and first circuit establishing means are arranged when energized electrically to connect the battery to the generator.

series field winding for operating the generator as a series motor to crank the prime mover. A first time delay means is provided connected to de-energize the first circuit establishing means after a predetermined time to break the cranking connection. A second circuit establishing means is provided arranged when energized electrically to connect the shunt field winding to the tablishing means is provided arranged when energized electrically to connect the armature of the generator to the battery for charging. Second time delay means is provided arranged to connect the second circuit establishing means for energization to energize the generator shunt field winding a predetermined time after the deenergisation of the first circuit establishing means and means responsive to operation of the f prime mover, such as a reverse current relay associated with the generator, is provided and connected to energize the third circuit establishing means to connect the generator armature to the battery. A third time delay means is provided connected to deenergize the second circuit establishing means after a second predetermined time to disconnect the shunt field, however the reverse current relay is connected to render ineffective the third time delay means if the prime J mover is operating.

Summarized, the engine is cranked for a predetermined time with the generator being operated as a series motor energized by the battery. In the event that the engine does not fire, the cranking connection is broken after the predetermined cranking period. However, if the engine does fire, it is allowed to idle at no load for a second predetermined time. At the conclusion of this period, the shunt field is energized and if the engine has fired, the generator armature is connected across the battery for charging. However, if the engine has not fired, the armature is not connected to the battery and the shunt field is disconnected.

The single figure of the drawing schematically illustrates the improved prime mover starting system of this invention.

Referring now to the drawing, there is shown a prime mover, such as a diesel engin mechanically connected to drive a generator 2. The generator 2 is provided with a commutating field exciting winding 3, a series field exciting winding 4 and a shunt field exciting winding 5. A battery 5 is provided connected to positive control line 1 and negative control line 8. A voltage regulater 9 is provided and since voltage regulators are well known in the art, it will not be hereinafter more fully described. The remaining components and their functioning can best be described in connection with the description of the operation of the system.

The starting sequence is initiated by the operator manually depressing the start switch thus closing contacts ES-I and ES-2, and opening battery for energization and. a third circuit es- 55 contact ES-3. It will be seen that contact 315-! 3 is connected to the positive supply line I through lines a and it to the operating coil of time delay relay TDC through lines it and is with contact DORE of relay DCR being interposed in series therewith. The operating coil of relay TDC is, of course, also connected to the negative control line Thus depressing of the start switch closing contact ES-i picks up relay TDC through normally closed contact DCRE of relay DCR. It will also be seen that contact ES-l of the manually operable start switch is connected to the o crating coil of relay DCR through lines. ll, 12 and it with normally open contact TDCi of relay T130 being interposed in series there with. Thus, when relay TDC is picked up responsive to closing of start switch contacts ESE, its normally open contact TDCi will be closed picking up relay DCR. Picking up of relay DCR opens contact DORE, thus deenergizing the oper ating coil of relay TDC. Relay TDC has atime delay dropout, for example, 20 seconds, and thus starts to time out. Relay DOB, picking up closes contacts BUR-i and and normally open contacts DCR3 Since the start switch is only momentarily depressed, contact L'St is now closed andthe operating coil of the relay DCE, which is, of-course, also connected tothe negative control line 8, is now connected for energization through the normally closed start switch contact E53, DCRcontaot DCRE, line M, line H, line it; DCR

normally open interlock contact DCRE, and lines l5,; It and ill to the positive control line i. Re-

lay DCR is thus sealed in through contact of the start switch, and its interlocks DCRi and [it-3R3. The operating coil of relay DS is connected tothe negative control line Band to line IZthrough line H, normally open contact TDCZ of relay TDC, normally open contact DCRE ofirelay DCR. Since at this instant, relay TDC is still timing out and its contact TDCZwill still be closed,;relay D8 will be picked up from the positive control line '5 through lines M), l6, l5, contact DCRt of relay DCR, contact DCReof rela-y DCR, contact TDCZ of relay TDC and. line H. It'will be seen that the operating coil of time delay. relay TBC is connected between the negative control line 3 and the positive control line lby contact of relayDS. Thus, when the relay DS is picked up, T30 is also picked up through line it, contact DSS of relay DS, and lines 11-], I6 and i l.- Picking up of time delay relay TBC in turn energizes the operating coil of relay DSR through lines ii], 9' and 20, contact TBC! of time delay relay "BBQ-and line 26, the other side of the operating coil of relay DSR being connected to the negative control line 8. It will also be readily seen that the picking up of relay BS closes contact DSl connecting the series cranking field of the generator 2 to the battery ii so that the generator is energizedas a series motor to crank the diesel l. Closing oi starting switch contact ESQ energizes diesel operating rela-y DOE to actuate the diesel governor (not shown). This relay seals itself in through its normally open contact DOB-i.

As hereinbefore described, upon manually depressing the starting switch, relays DCR, DS, TBQ'DSR, TDC and DOE are picked up and the series field winding 4 of the generator 2 is connected to the battery t operating the generator as a series motor for cranking the diesel. Time; delay relay TDC was initially picked up but is now deenergized and is timing out. After the requisite time delay, relay TDC drops out and the opening of its contact TDCZ deenergizes re- 4 lay DS. This in turn opens contact DSI disconnecting the series cranking fielcl 4 from the battery El so that the generator 2 is no longer operated as a motor to crank the diesel. The deenerigzaticn of relay DS also opens its contact BS3 deenerigizing time delay relay 'IBC which has a predetermined drop out time, for example. 1i) seconds and thus this relay starts to time out. Dropping out of relay DS also recloses its normally closed contact BS2 in the circuit of the relays DEC and BBF. When relay TBC times out after the predetermined time delay, its normally closed contact TBC2 in the circuit of relaysDBCand DEF also closes and its contact TBCI in the circuit of relay DSR opens. Capacitor 29 is connected across the coil of relay DSR, however, and, thus delay the dropout of relay DEB for a short period, for example, 1 second. Thus, contact DSR! in the circuit of relays DB0 and DBF remains closed momentarily after contacts D552 andflBCZ have reclosed. Thus, relay DBI" picks up [closing contact DBF'i connecting the generator shunt-field winding 5 to thevolt: age regulator 53 .forsenergization. i has fired is running, the voltage build-up in the misnomer, the generator 2 will-cause the reverse current relayRCRB to pick up. The

operating coil of relay BBC is connected to thenegative control lineswwith contact RCRBI 0i reversecurrent relay RCRB being a-rranged-in.

series therewith, the other side of the .coil of relay BBC being connected to positive control it line i through lines 22, normally closed contacts 3c of the stop switch, normally closed contactsTBCZ of relay TBC, line 25,: normally open contacts DSBl of relay D SR, line 26, and-normally closed contactsDSZoi relay DS. It-will be noted that operating coil of relay DBF.i .con-,

nected across the operatingcoil of relay DEC and.

contact RCRB! of=relay RCRB. Picking up of reverse current relay RCRB closes its contact RCRBi picking up relayYDBC. This closes interlock DBGZ ofrelay BBC scaling in relay DSR, content BBC?) being connectedacross. contact, Picking up of relay TBClby lines 21 and;28. DBC also closesits contact DBCi connecting the armature of generator 2 across the battery '6 for charging. Sealing in ofrelay DSR through the contact DBCZ insures that contact-DSR! in a circuit of relays BBC and DEF remains closed thus keeping DB0 and DEF energized. It will thus be readily seen that relays DSR, DBC, DBP and RCRB are energized with the shunt field winding 5 of generator 2 connected for energiza-tion'irom the voltage regulator 9 and the armature of generator 2 connected to-the battery Efor charging.

In the event that the diesel l ha d, not -fi-red,

reverse current relay RCRB would not have picked up soits contact RCRBi would not have closed to pick up relay DBC. Relay DSR would then have dropped out after the time delay caused by the capacitor 29 thus opening the circuit of relay DBF and disconnecting the shunt field winding Fa hom the voltage regulator 9 to re- 'move field excitation from the generator 2.

will be seen. that under these conditions, the

system is entirely shut down and another manual closing of the starting switch is necessary to again attempt to start the system. If, however,

the diesel. has satisfactorily started and isconnected to the battery for-charging, it can be stopped by manually depressing the stop switch This opens the, circuits of relays DOB, DBC and DB F dropping opening contacts 24 and 30;

If 1 the diesel 1 out these relays, deactuating the diesel governor and disconnecting the shunt field winding 5 from the voltage regulator 9 and the armature of generator 2 from the battery 6. Dropping out of relay DB and opening of its contact DBCZ will drop out relay DSR to open its contact DSRI so that relays DB0 and DBF remain dropped out after the momentary opening and reclosing of the manually actuated stop switch.

To summarize the operation of this system, momentarily depressing the manually operated start switch picks up time delay relay TDC which in turn picks up relay DCR. Relay DCR seals itself in through its interlock and opens the circuit of time delay relay TDC which starts to time out. With rela-y DCR. picked up and the contacts relay TDC still closed, relay D8 will pick up connecting cranking field 4 of the generator 2 to battery to crank the diesel and also energizing time delay relay TBC. When relay TDC times out, contact TDC2 opens the circuit of relay DS thus disconnecting the cranking field 4 from the battery 6 and also initiating the time delay drop-out of relay TBC. Relay DSR was picked up by contact TBCI of time delay relay TBC and thus its contact DSRI is closed. Since relay DS was dropped out by the time delay opening of relay TDC, its contact DS2 is closed and when time delay relay TBC times out, contact T302 will close, thus picking up relay DBF connecting shunt field winding 5 of generator 2 to the voltage regulator 9. It is thus seen that the diesel is allowed to idle at no load during the duration of the time delay drop-out of relay TBC. If the diesel has fired, closing of the oircuit of the shunt field exciting winding by the picking up of relay DBF will energize reverse current relay RCRB closing its contact RCRB! to energize relay DBC which connects the armature of generator 2 to the battery 6 for charging. Opening of contact TBCI of time delay relay 'IBC would normally drop out relay DSR preventing energization of relays DB0 and DBF, however, opening of relay DSR is momentarily prevented by capacitor 29 and in the event that reverse current relay RCRB is picked up closing its contact RCRB! to energize relay DBC, relay DSR is sealed in through interlock contact DBC2 of relay DBC. If the diesel has not fired, or in the event that the generator 2 is not operating satisfactorily, reverse current relay RCRB will not pick up and relay BBC will not be energized, thus allowing relay DSR to drop out opening the circuit of relay DB0 and DBF disconnect the shunt field 5 from the voltage regulator 6.

It will now be seen that in accordance with this system, the prime mover is initially cranked for a predetermined period of time using its mechanically connected generator as a series motor energized from the battery. After the predetermined cranking time, the cranking connection is broken and the prime mover is allowed to idle for a second predetermined period after which the shunt field of the generator is energized and in the event that the prime mover has fired, the armature of the generator is connected across the battery for charging. On the other hand, if the prime mover has not fired, the shunt field is disconnected.

It will now be readily apparent that this invention provides an improved starting system for a prime mover, such as a diesel engine, characterized by its automatic progression to the various successive steps after initial manual actuation, and further characterized by the provision of safety features which disconnect the cranking field of the generator from the battery after a predetermined time in order to prevent current drain on the battery and excessive current flow in the generator if the prime mover does not start, and which further disconnects the shunt field connection in the event that the prime mover has not fired or the generator is not producing a predetermined voltage.

While I have shown and described a particular embodiment of this invention, further modifications and improvements will occur to those skilled in the art and I intend in the appended claims to cover all modifications which do not depart from the spirit and scope of this invention.

What I claim. as new and desire to secure by Letters Patent of the United States is:

l. A system for starting a thermal prime mover comprising a generator mechanically connected to said main prime mover, a battery, a circuit establishing means arranged when actuated electrically to connect said battery to said generator for operating the same as a motor to crank said prime mover, time delay means connected to deactuate said circuit establishing means after a predetermined time, said time delay means being independent of said generator current, and

means responsive to operation of said prime mover arranged electrically to connect said generator to said battery for charging.

2. A system for starting a thermal prime mover comprising a generator mechanically connected to said prime mover, a battery, a first circuit establishing means arranged when actuated electrically to connect said battery to said generator for operating the same as a motor to crank said prime mover, time delay means connected to deactuate said first circuit establishing means after a predetermined time, said time delay means being independent of said generator current, second circuit establishing means arranged when actuated electrically to connect said generator to said battery for charging, and means responsive to operation of said prime mover connected to actuate said second circuit establishing means.

3. A system for starting a thermal prime mover comprising a generator mechanically connected tosaid prime mover, a battery, 2. first circuit establishing means arranged when actuated electrically to connect said battery to said generator for operating the same as a motor to crank said prime mover, time delay means connected to deactuate said first circuit establishing means after a predetermined time, said time delay means being independent of said generator current, second circuit establishin means arranged when actuated electrically to connect said generator to said battery for charging, and means responsive to the voltage produced by said generator connected to actuate said second circuit establishing means.

4. A system for starting a thermal prime mover comprising a generator mechanically connected to said prime mover and having a series field exciting winding and a shunt field exciting winding, a battery, a first circuit establishing means arranged when actuated electrically to connect said battery to said series field winding for operating said generator as a motor to crank said prime mover, time delay means connected to deactuate said first circuit establishing means after a predetermined time, a second circuit establishing means arranged when actuated electrically toconnect said shunt field winding for energization, a third circuit establishing means arranged when actuated electrically to connect the armature of said generator to said battery for charging, and means responsive to operation of said prime mover connected to actuate said third circuit establishing means.

5. A system for starting a thermal prime mover comprising a generator mechanically connected to said prime mover and having a series field exciting winding and a shunt field exciting winding, a battery, first circuit establishing means arranged when actuated electrically to connect said battery to said series field winding for op erating said generator a motor to crank said prime mover, time delay means connected to deactuate said first circuit establishing means after a predetermined time, a second circuit establishing means arranged when actuated electrically to connect said shunt field winding for energize tion, third circuit establishing means arranged when actuated electrically to connect the armature of said generator to said battery for charging, and responsive to the voltage produced by said generator connected to actuate said third circuit establishing means.

6. A system for starting a thermal prime mover comprising a generator mechanically connected to said prime mover and having a series field exciting winding and a shunt field exciting winding, a battery, a first circuit establishing means arranged when actuated electrically to connect said. battery to said series field winding for operating said generator as a motor to crank said prime mover, first time delay means connected to deactuate said first circuit establishing means after a predetermined time, a second circuit establishing means arranged when actuated electrically to connect said shunt field winding for energization, a third circuit establishing means ar ranged when actuated electrically to connect the armature of said generator to said battery for charging, second time delay means connected to actuate said second circuit establishing means a predetermined time after deactuation of said first circuit establishing means, and means responsive to operation of said prime mover connected to actuate said third circuit establishing means.

7. A system for starting a thermal prime mover comprising a generator mechanically connected to said prime mover and having a series field exciting winding and a shunt field exciting winding, a battery, a first circuit establishing means arranged when actuated electrically to connect said battery to said series field winding for operating said generator as a motor to crank said prime mover, a first time delay means connected to deactuate first circuit establishing means after a predetermined time, a second circuit eotablishin arranged when actuated electrically to connect said shunt field winding for en rgization, a third circuit establishing means arranged when actuated electrically to connect the armature or generator to said battery for charging, means responsive to operation of said prime mover connected to actuate said third circuit establishing means, and a second time delay means connected to deactuate said second circuit establishing means after a predetermined time, said prime mover operation responsive means (ill 8 being connected to render ineffective said second time delay means responsive to operation of said prime mover.

8. A system for startinga thermal prime mover comprising a generator mechanically connected to said prime mover and having a series field exciting winding and a shunt field exciting winding, a battery, first circuit establishing means arranged when actuated electrically to connect said battery to said series field winding for operating said generator as a motor to crank said prime mover, time delay means connected to deactuate said first circuit establishing means after a predetermined time, a voltage regulator, a second r circuit establishing means arranged when actuated electrically to connect said shunt field winding to said voltage regulator for energization, a third circuit establishing means arranged when actuated electrically to connect the armature of said generator to said battery for charging, and means responsive to operation of said prime mover connected to actuate said third circuit establishing means.

9. A system for starting a thermal prime mover comprising a generator mechanicall connected to said prime mover and having a series field exciting winding and a shunt field exciting winding, a battery, first circuit establishing means arranged when actuated electrically to connect said battery to said series field winding for operating said generator as a motor to crank said prime mover, a first time delay means connected to deactuate said first circuit establishing means after a predetermined time, a second circuit establishing means arranged when actuated electricaliy to connect shunt field winding for energization, a third circuit establishing means arranged when actuated electrically to connect the armature of said generator to said battery for charging, second time delay means connected to actuate said second circuit establishing means a predetermined time after deactuation of said first circuit establishing means, means responsive to operation of said prime mover connected to actuate said third circuit establishing means, and a third time delay means connected to deactuate said second circuit establishing means after a predetermined time delay, said prime mover operation responsive means being connected to render ineffective said third time delay means responsive to operation of said prime mover.

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